From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Fri, 12 Dec 2014 19:25:33 +0000 (-0300)
Subject: perf evlist: Improve the strerror_mmap method
X-Git-Tag: omap-for-v3.20/drop-legacy-3517~25^2~1^2~15
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e965bea1ad1a8062b306f7fcc5c3e05dc5213b7c;p=pandora-kernel.git

perf evlist: Improve the strerror_mmap method

Considering the per user locked pages limit, improve the message when a
user uses multiple simultaneous perf mmap calls:

When the request is more than the current maximum:

  [acme@ssdandy linux]$ trace -m 128 usleep 1
  Error: Operation not permitted.
  Hint:  Check /proc/sys/kernel/perf_event_mlock_kb (516 kB) setting.
  Hint:  Tried using 516 kB.
  Hint:  Try 'sudo sh -c "echo 1032 > /proc/sys/kernel/perf_event_mlock_kb"', or
  Hint:  Try using a smaller -m/--mmap-pages value.
  [acme@ssdandy linux]$

And when the limit is less than that:

  [acme@ssdandy linux]$ trace -m 512 usleep 1
  Error: Operation not permitted.
  Hint:  Check /proc/sys/kernel/perf_event_mlock_kb (2056 kB) setting.
  Hint:  Tried using 2052 kB.
  Hint:  Try using a smaller -m/--mmap-pages value.
  [acme@ssdandy linux]$

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-yqdie3c8qvdgenwleri267d4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---

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